A conventional smartphone is produced in the form of a product having a rigid display, and chemically strengthened glass used to protect the surface of the display. Recently, as novel flexible displays such as curved and bendable displays have come to be utilized in smartphones, it is necessary to develop a cover window for protecting the surface of such a flexible display.
Hence, required is a material suitable for use in the cover window, simultaneously satisfying optical properties, such as a total transmittance of at least 90 to 92% and a haze of 1 to 2%, and physical properties, such as a surface pencil hardness of at least 4 to 6 H.
Moreover, among various materials available for displays, in the case where film layers having different refractive indices, such as a polarizer film, a phase difference film, and a transparent conductive film, are stacked or laminated, optical interference, such as interfacial reflection, or a rainbow or Newton ring phenomenon, attributable to the mismatching of refractive indices, may occur. With the goal of solving these problems, matching of refractive indices is required. In order to set refractive indices to suit the production processes of different display manufacturers, a variety of materials having different refractive indices have to be used, and thus there is a need for a coating composition satisfying the aforementioned optical and physical properties.